System for pretreating the lumen of a catheter

Abstract

A method of and system for pretreating the lumen of a catheter or small diameter tubing. A vacuum chamber includes a microwave port and a microwave supply subsystem including a microwave generator, and a circular polarizer produces circularly polarized microwaves propagated into the vacuum chamber via the port at a frequency which produces electron cyclotron resonance. A magnetic coil about the vacuum chamber generates a magnetic field in the vacuum chamber with magnetic field lines co-linear with the propagation direction of the microwaves. A catheter manifold positions at least one catheter in the vacuum chamber and supplies a gas within the catheter lumen to generate a plasma in the lumen for pretreating the same.

1 . A system for pretreating the lumen of a catheter or small diameter tubing, the system comprising:
 a vacuum chamber including a microwave port;   a microwave supply subsystem including:
 a microwave generator, and 
 a circular polarizer producing circularly polarized microwaves propagated into the vacuum chamber via the port at a frequency which produces electron cyclotron resonance; 
   a magnetic coil about the vacuum chamber generating a magnetic field in the vacuum chamber with magnetic field lines co-linear with the propagation direction of the microwaves; and   a catheter manifold positioning at least one catheter in the vacuum chamber and supplying a gas within the catheter lumen to generate a plasma in the lumen for pretreating the same.   
   
   
       2 . The system of  claim 1  in which the microwaves are right-handed circularly polarized and the magnetic field is parallel to the microwave propagation direction. 
   
   
       3 . The system of  claim 1  in which the microwaves are left-handed circularly polarized and the magnetic field is anti-parallel to the microwave propagation direction. 
   
   
       4 . The system of  claim 1  further including a gas inlet into the vacuum chamber supplying gas about the catheter to generate a plasma for pretreating the exterior of the catheter. 
   
   
       5 . The system of  claim 1  in which the catheter manifold includes a proximal fixture for one end of the catheter and a distal fixture for the other end of the catheter, the distal fixture connected to a gas outlet conduit. 
   
   
       6 . The system of  claim 5  in which the proximal fixture includes a main gear driving a planetary gear fixed to a proximal connector for rotating the catheter for a more uniform plasma treatment. 
   
   
       7 . The system of  claim 6  in which there are multiple connectors each rotated via a planetary gear. 
   
   
       8 . The system of  claim 1  in which the microwave generator produces microwaves at a frequency between 1 GHz and 30 GHz. 
   
   
       9 . The system of  claim 8  in which the microwave generator produces microwaves at a frequency of 2.45 GHz. 
   
   
       10 . The system of  claim 1  in which the magnetic coil is wound to produce a magnetic field axially decreasing in strength producing a magnetic beach in the vacuum chamber aiding in microwave transmission and heating the plasma. 
   
   
       11 . The system of  claim 1  in which the catheter manifold includes means for rotating the catheter around the catheter's longitudinal axis. 
   
   
       12 . The system of  claim 1  in which the catheter manifold includes means for linearly translating the catheter within the vacuum chamber. 
   
   
       13 . A method of pretreating a lumen of a polymer catheter so it can be coated with a bioactive material, the method comprising:
 generating circularly polarized microwaves at a frequency which produces electron cyclotron resonance and propagating the microwaves to a plasma zone;   producing a magnetic field in the plasma zone with magnetic field lines co-linear with the propagation direction of the microwaves; and   subjecting the polymer catheter to the plasma zone and introducing a gas in the lumen thereof generating plasma in the lumen which pretreats the same.   
   
   
       14 . The method of  claim 13  further including pretreating the outer surface of the polymer catheter. 
   
   
       15 . The method of  claim 13  further including the step of coating the pretreated polymer catheter with a bioactive material. 
   
   
       16 . The method of  claim 15  in which the bioactive material includes anti-microbial material. 
   
   
       17 . The method of  claim 15  in which the bioactive material includes anti-thrombogenic material. 
   
   
       18 . The method of  claim 16  in which the anti-microbial material includes selenium, silver, penicillin, tetracycline, sulfa drugs, quaternary ammonium compounds, octenidine dihydrochloride. 
   
   
       19 . The method of  claim 17  in which the anti-thrombogenic material includes heparin, antithrombin-III—heparin (ATH), collagen, poly hexamethylene biguanide hydrochloride, adenosine diphosphatase (ADPase), tissue factor pathway inhibitor (TFPI), nitric oxide, polyethylene oxide, tetra ethylene glycol ether (tetraglyme), thrombomodulin, pentasaccharides, hirulog, hirudin, PPACK, phosphorl choline, plasminogen activators, peptides, heparin cofactor II, aspirin anhydrides, polyethylene oxide conjugated compounds, and mixtures of the above. 
   
   
       20 . The method of  claim 13  further including the step of coating the pretreated polymer catheter with a monomer base layer for coupling with a bioactive material. 
   
   
       21 . The method of  claim 20  in which the monomer base layer is glycidyl methacylate, acrylic acid, acrylamide, allyl alcohol, allyl amine, methacryl chloride, isocyanate ethyl methacrylate ammonium, fluorohydrocarbons, glycidyl acrylate, acryloyl chloride, and/or modified albumin. 
   
   
       22 . The method of  claim 13  in which the polymer catheters are fabricated of polyurethane, silicone rubber, polyethylene, polypropylene, polycarbonate, polyester, polystyrene, polymethyl methacrylate, and their co-polymers and/or fluorinated hydrocarbons. 
   
   
       23 . The method of  claim 13  in which generating circularly polarized microwaves includes employing a magnetron generator with a hybrid polarizer to convert linearly polarized microwaves to circular polarization. 
   
   
       24 . The method of  claim 22  in which the generator operates at a frequency between 1 GHz and 30 GHz. 
   
   
       25 . The method of  claim 22  in which the generator operates at a frequency of 2.45 GHz. 
   
   
       26 . The method of  claim 13  in which producing the magnetic field includes creating a magnetic beach. 
   
   
       27 . The method of  claim 13  in which a plasma is formed in a flowing or static gas and the plasma zone is defined by the lumen wall of a catheter. 
   
   
       28 . The method of  claim 13  in which plasma is formed in a flowing or static gas, and the plasma zone is defined by a vacuum chamber. 
   
   
       29 . The method of  claim 28  in which the vacuum chamber is vertically oriented with an external solenoid magnet for producing the magnetic field. 
   
   
       30 . The method of  claim 13  in which introducing a gas includes the use of a differential pumping system connected both to a vacuum chamber and to the catheter lumen to cause plasma formation within the lumen region. 
   
   
       31 . The method of  claim 13  in which introducing a gas includes introducing a Penning gas mixture into the lumen to assist in the initiation of the plasma. 
   
   
       32 . The method of  claim 31  in which the Penning gas mixture includes mixtures of argon and helium, neon and helium, argon and neon, neon and krypton, and/or argon and krypton. 
   
   
       33 . The method of  claim 13  further including inserting a fine metallic wire into the catheter lumen to assist in the initiation of the plasma. 
   
   
       34 . The method of  claim 33  in which the wire material includes titanium. 
   
   
       35 . The method of  claim 13  further including adding a material to the lumen wall to assist in the initiation of the plasma. 
   
   
       36 . The method of  claim 35  in which the material is titanium powder. 
   
   
       37 . The method of  claim 35  in which the material is titanium oxide powder. 
   
   
       38 . The method of  claim 13  further including the step of rotating the catheter around its longitudinal axis for a more uniform plasma surface treatment. 
   
   
       39 . The method of  claim 13  further including the step of longitudinally translating the catheter for a more uniform external plasma surface treatment. 
   
   
       40 . The method of  claim 13  in which the microwaves are right-handed circularly polarized and the magnetic field is parallel to the microwave propagation direction. 
   
   
       41 . The method of  claim 13  in which the microwaves are left-handed circularly polarized and the magnetic field is anti-parallel to the microwave propagation direction. 
   
   
       42 . A polymer catheter pretreated by the method of  claim 13 . 
   
   
       43 . The method of  claim 13  further including the step of coating the pretreated polymer catheter with hydrophilic compounds. 
   
   
       44 . The method of  claim 43  in which hydrophilic compounds include poly ethylene glycol, hyaluronic acid polysaccharides, polyvinyl alcohol, polyisopropyl allylamide, polyvinyl pyrrolidinone, star polymers and/or dendrimers derived from the same. 
   
   
       45 . The method of  claim 13  further including the step of coating the pretreated polymer catheter with hydrophobic compounds. 
   
   
       46 . The method of  claim 45  in which hydrophobic compounds include fluorocarbons, saturated hydrocarbons, and their self assembled monolayers.